1. Field of Use
This invention relates to imaging and reading (decoding) apparatus and methods of imaging and reading; and more particularly, to imaging and reading of encoded symbology applied, directly or indirectly, to articles and methods of effecting such imaging and the reading thereof.
2. Description of the Prior Art
More and more, modern technology requires accurate, efficient and rapid availability of things. Things to be manufactured and to be used in manufacturing processes. Things to be placed in storage and removed from storage and/or loaded for transport and unloaded after transport.
It has, therefore, become important to keep track of such things or articles as such things may otherwise be referred to. Knowledge of the existence, location and physical and other characteristics of such articles facilitates a more effective employment of such articles; especially if such knowledge is gathered and stored in a consistent and automated manner and, when required, utilized in an automated manner.
Robotic handling of parts for processing such as machining or assembly purposes and for automated sorting, transportation, manipulation and other handling of parts, components, assemblies, goods, packages, and the like usually requires that some form of machine readable code or symbology be applied to the article. The subsequent reading (decoding), collecting, interpretation and utilization of article applied machine readable codes, by devices and systems utilized for such purposes, has been found to be an effective tool of modern industry and society. U.S. Pat. No. 5,567,927 to R. W. Kahn for "Apparatus For Semi-Conductor Wafer Identification" and U.S. Pat. No. 5,631,456 to K. L. Kost for "Reflection Control Apparatus" are exemplary of such product marking. At times it is convenient to apply the symbology to a media such as a pressure sensitive label. Other times it is more desirable and possibly more efficient to apply the symbology directly to the article.
The symbology may be a conventional bar code, a stacked bar code or other 2-D symbology.
Reading of such symbologies, as by a stationary or hand-held reader or imager, requires proper and accurate imaging of the symbology which, in turn, requires proper illumination of the symbology so that an accurate image of the entire symbology is captured, stored, interpreted and utilized. Illumination and imaging of symbology quite often presents problems if the media carrying the symbology is applied to an irregular or curved surface. Such problems may be more pronounced if the symbology is applied directly to the article and if the article surface is normally specular and/or if the article's surface is irregular, and/or if the symbology is of low contrast such as one accomplished by laser etching or dot peening.
When the symbology reader or imager is to be hand-held it is usually most desirable to minimize its size and weight; as well as the time required to effectively and efficiently capture the image of the symbology. Managing and conserving the power necessary to illuminate and capture the image of the symbology and to effect other processing to be accomplished within the hand-held device is also an important factor. The configuration of the body of a hand-held imager to be grasped and held while locating and capturing the image of the symbology and the length of time required to do so is of significant importance. Movement of the imager while capturing the image may affect the ability of the device to capture the image and the accuracy of the image itself when compared to the symbology. The shorter the time required to capture the image the greater the probability that the image captured will be interpreted to correspond to the symbology.
U.S. Pat. No. 4,766,300 to G. E. Chadima. Jr., et al for "Instant Portable Bar Code Reader" and U.S. Pat. No. 5,314,372 to J. A. S. Bjorner et al for "Apparatus For the Uniform Illumination Of A Surface", show and describe symbology readers which must be positioned against the symbology in order to properly image and interpret the symbology; and thus limit the versatility of the device and possibly its acceptability. On the other hand imagers such as those shown in U.S. Pat. No. 5,430,285 to T. W. Karpen et al for "Illumination System For Optical Reader" and in U.S. Pat. No. 5,585,616 to D. L. Roxby et al for "Camera For Capturing And Decoding Machine-Readable Matrix Symbol Images Applied to Reflective Surfaces" and in U.S. Pat. No. 5,689,104 to M. Suzuki et al for "Optical Code Reader With Devices To Locate A Code In A Reading Window" may be utilized at predetermined distances from the symbology but present other characteristics and shortcomings which may render them unacceptable.
Other imagers and systems are shown and described in U.S. Pat. No. 5,702,059 to J. B. Chu et al for "Extended Working Range Dataform Reader Including Fuzzy Logic Image control Circuitry" and in U.S. Pat. No. 5,756,981 to A. R. Roustaei et al for "Optical Scanner For Reading And encoding One-And Two-Dimensional Symbologies At Variable Depths Of Field Including Memory Efficient High Speed Image Processing Means And High Accuracy Image Analysis Means"; but these imagers and systems also may be unacceptable because they may not meet the above described criteria.